Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #27283

Re: callback function

From "Bill Cunningham" <billcun@suddenlink.net>
Newsgroups comp.lang.c
Subject Re: callback function
Date 2012-10-17 17:50 -0400
Organization Aioe.org NNTP Server
Message-ID <k5n96a$ikj$1@speranza.aioe.org> (permalink)
References <k5n77p$e5v$1@speranza.aioe.org> <1o8u781nrpll3im14bf0019tg1523qv226@4ax.com>

Show all headers | View raw

Barry Schwarz wrote:
> On Wed, 17 Oct 2012 17:16:51 -0400, "Bill Cunningham"
> <billcun@suddenlink.net> wrote:
>
>>    I have these 3 functions and before I compile I am going to ask
>> about them. This is for qsort. I tried to tackle this once and
>> couldn't get it I think I get it now. I don't like const's. They are
>> a nuisance. You can't directly pass string literals to them you want
>> to change. Maybe that's just the way C is though.
>
> Since changing a string literal is prohibited, you are doomed before
> you start.
>
>>
>> #include <stdio.h>
>> #include <stdlib.h>
>>
>> int comp(constvoid *a,const void *b)
>
> Wouldn't using cut and paste be easier than retyping?  It would also
> eliminate silly errors like parameter 1 as well as provide some clue
> that this is your actual code.
>
>> {
>>     int *ia=(constint *)a;
>
> Doesn't this generate a diagnostic?  Either you make ia const or you
> cast away the const from a.
>
>>     int *ib=(const int *)b;
>>     return *ia-*ib;

Ok like int *ia=(int *)b;    ?

> Are you sure this never overflows?

    Like I said at the beginning of my post. This is untested code.

>> }
>>
>> void print_int_array(int *array,size_t len)
>> {
>>    size_t i;
>>    for (i=0;i<len;i++)
>
> Did you run out of horizontal white space or do you just enjoy
> cramming your text together to make it harder to read?
>
>>    printf("%d | ",array[i]);
>
> Still having problems with indenting?
>
>>    putchar('\n');
>> }
>>
>> void sort_int(void)
>> {
>>    int num={1,3,6,4,5};
>
> Did you mean for num to be an array?
>
>>    size_t num_len=sizeof num/sizeof (int);
>> }
>>
>> 1 because of qsorts comp callback function parameters include a
>> const do I need them and can I remove them as I have in the callback?
>
> You didn't remove any const in comp().  Maybe you meant to but are
> just posting code of the top of your head.
>
>> 2. second line of sort_int. num is not a built in type so it doesn't
>> require parenthesis does it?
>
> What????  num is an object of type int which certainly is built-in. Of
> course, you meant for it to be an array of int which is a built-in
> aggregate.  But then it would require brackets.

Yes I forgot the []. Ok I will rewrite.

Bill

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-17 17:16 -0400
  Re: callback function John Gordon <gordon@panix.com> - 2012-10-17 21:36 +0000
    Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-17 17:44 -0400
      Re: callback function John Gordon <gordon@panix.com> - 2012-10-17 21:51 +0000
        Re: callback function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-18 00:11 +0100
        Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:37 -0400
          Re: callback function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-19 01:16 +0100
          Re: callback function Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-20 06:48 -0700
    Re: callback function Ian Collins <ian-news@hotmail.com> - 2012-10-18 10:45 +1300
      Re: callback function pete <pfiland@mindspring.com> - 2012-10-19 14:49 -0400
        Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 16:59 -0400
        Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 17:04 -0400
          Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-19 14:14 -0700
            Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 17:31 -0400
              Re: callback function Keith Thompson <kst-u@mib.org> - 2012-10-19 14:54 -0700
                Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 18:42 -0400
    Re: callback function James Kuyper <jameskuyper@verizon.net> - 2012-10-17 17:47 -0400
    Re: callback function tom st denis <tom@iahu.ca> - 2012-10-19 04:44 -0700
      Re: callback function James Kuyper <jameskuyper@verizon.net> - 2012-10-19 08:24 -0400
  Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-17 14:39 -0700
    Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-17 17:50 -0400
      Re: callback function Ian Collins <ian-news@hotmail.com> - 2012-10-18 11:00 +1300
        Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:20 -0400
        Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:24 -0400
          Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-18 22:30 -0700
          Re: callback function Ian Collins <ian-news@hotmail.com> - 2012-10-20 11:58 +1300
            Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 19:27 -0400
              Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 19:43 -0400
                Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-19 21:09 -0700
          Re: callback function Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-20 06:53 -0700
      Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-17 19:25 -0400
        Re: callback function Ian Collins <ian-news@hotmail.com> - 2012-10-18 13:34 +1300
          Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-17 20:41 -0400
            Re: callback function Ian Collins <ian-news@hotmail.com> - 2012-10-18 14:37 +1300
              Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:17 -0400
                Re: callback function Ian Collins <ian-news@hotmail.com> - 2012-10-20 11:54 +1300
              Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:54 -0400
                Re: callback function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-19 01:23 +0100
                Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 20:32 -0400
                Re: callback function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-19 02:43 +0100
                Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 16:56 -0400
                Re: callback function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-19 22:10 +0100
                Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-18 22:30 -0700
                Re: callback function Kenneth Brody <kenbrody@spamcop.net> - 2012-10-19 12:37 -0400
                Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 16:52 -0400
    Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-19 18:44 -0400
      Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-19 21:09 -0700
        Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-20 15:01 -0400
          Re: callback function Keith Thompson <kst-u@mib.org> - 2012-10-20 12:47 -0700
          Re: callback function Les Cargill <lcargill99@comcast.com> - 2012-10-20 14:51 -0500
          Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-20 14:39 -0700
            Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-20 19:06 -0400
              Re: callback function Barry Schwarz <schwarzb@dqel.com> - 2012-10-20 22:22 -0700
                Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-21 14:35 -0400
                Re: callback function Kenneth Brody <kenbrody@spamcop.net> - 2012-10-22 10:58 -0400
              Re: callback function Bill Cunningham <billcun@suddenlink.net> - 2012-10-24 17:28 -0700
          Re: callback function Ian Collins <ian-news@hotmail.com> - 2012-10-21 11:32 +1300
            Re: callback function Keith Thompson <kst-u@mib.org> - 2012-10-20 15:51 -0700
      Re: callback function Robert Miles <milesrf@Usenet-News.net> - 2012-11-25 22:39 -0600
  Re: callback function Keith Thompson <kst-u@mib.org> - 2012-10-17 17:51 -0700
    Re: callback function Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-10-18 20:34 +0300
    Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:15 -0400
      Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:27 -0400
      Re: callback function Keith Thompson <kst-u@mib.org> - 2012-10-18 15:47 -0700
        Re: callback function "Bill Cunningham" <billcun@suddenlink.net> - 2012-10-18 18:52 -0400
      Re: callback function blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2012-10-25 10:01 +0000
        Re: callback function Kenneth Brody <kenbrody@spamcop.net> - 2012-10-25 12:44 -0400
          Re: callback function blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2012-10-26 12:48 +0000
  Re: callback function Robert Miles <milesrf@Usenet-News.net> - 2012-11-25 22:13 -0600
    Re: callback function Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-26 03:42 -0800
    Re: callback function James Kuyper <jameskuyper@verizon.net> - 2012-11-26 06:59 -0500
    Re: callback function Keith Thompson <kst-u@mib.org> - 2012-11-26 23:03 -0800

csiph-web